分子马达（如 ATP 合酶）如何把化学能转成机械转动？
How does a molecular motor like ATP synthase turn chemical energy into rotation?
质子顺浓度梯度流过 ATP 合酶的转子，像水流推水车，驱动催化位点把 ADP 和磷酸合成 ATP；这是纳米尺度的旋转马达。
Protons flowing down their gradient spin the rotor of ATP synthase like a waterwheel, driving sites that couple ADP and phosphate into ATP—a nanoscale rotary motor.
难度 专业 · 适合 小学高段(9-12)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Walker 与 Boyer，《ATP 合成的机制》（诺贝尔讲座，1997）
Walker & Boyer, 'The Mechanism of ATP Synthesis' (Nobel Lectures, 1997)
#分子马达 #ATP合酶 #能量转换
光镊和原子力显微镜如何测量单个分子的作用力？
How do optical tweezers and AFM measure forces on single molecules?
光镊用聚焦激光捕获并拉伸与微球连接的生物大分子，原子力显微镜用悬臂探针直接拨动分子，通过位移与已知刚度换算出皮牛级力与解折叠路径。
Optical tweezers trap and stretch a biomolecule tethered to a bead with focused laser; AFM uses a cantilever probe to pull the molecule, converting displacement via known stiffness into piconewton forces and unfolding pathways.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Nature Physics — 单分子生物物理
Nature Physics — single-molecule biophysics
#光镊 #原子力显微镜 #单分子
解旋酶打开DNA双链需要克服什么力？
What forces must helicase overcome to open the DNA double helix?
解旋酶沿DNA移动、用ATP供能拆开碱基对氢键并克服链间堆叠作用力，同时需处理随之产生的扭转应力；单分子力谱测得解旋力约在皮牛量级。
Helicase moves along DNA using ATP to break base-pair hydrogen bonds and overcome stacking forces while handling torsional stress; single-molecule force spectroscopy measures unwinding forces on the piconewton scale.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Nature Physics — 单分子生物物理
Nature Physics — single-molecule biophysics
#解旋酶 #DNA #单分子力谱
光遗传（optogenetics）如何用光“开关”神经元？
How does optogenetics switch neurons on and off with light?
把对光敏感的离子通道蛋白（如 Channelrhodopsin）表达到特定神经元，蓝光打开通道使细胞兴奋、黄光关断，实现对神经回路的毫秒级精准控制。
Light-sensitive channels like channelrhodopsin are expressed in chosen neurons; blue light opens them to excite, yellow light quiets—millisecond-precise control of circuits.
难度 专业 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Boyden 等，《毫秒量级、基因靶向的神经元活动光控》，Nature Neuroscience 8 (2005)
Boyden, Zhang, Bamberg, Nagel & Deisseroth, 'Millisecond-timescale, Genetically Targeted Optical Control of Neural Activity', Nature Neuroscience 8 (2005)
独立核验依据 · Independent verification: 核验依据 1 EUROPEPMC 标识 16116447：Millisecond-timescale, genetically
#光遗传 #离子通道 #神经
ATP合酶如何像旋转马达一样合成ATP？
How does ATP synthase synthesize ATP like a rotary motor?
ATP合酶是嵌在线粒体内膜的旋转马达：质子顺梯度回流驱动转子旋转，机械扭矩使催化结构域循环构象变化，把ADP和磷酸合成ATP。
ATP synthase is a rotary motor in the mitochondrial membrane: proton flow down its gradient spins the rotor, and the mechanical torque cycles catalytic conformations to synthesize ATP from ADP and phosphate.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：此条未指向带版次的可引用著作（通识性内容、机构文件或未展开的英文书名），本库不提供独立书目出处；如需精确引用，需由编辑补全具体篇目与版次。
Nature Physics — 生物分子机器
Nature Physics — biomolecular machines
#ATP合酶 #分子马达 #旋转
驱动蛋白在微管上的步长约为8纳米，与热涨落的尺度相当，它凭借什么机制保证长期单向行进而不显著后退？
Kinesin advances along a microtubule in steps of roughly eight nanometers, a scale comparable to thermal fluctuations — what mechanism lets it march persistently in one direction instead of wandering backward?
驱动蛋白的两个头部沿微管交替结合，ATP水解促使颈链接合，构象偏摆把后侧头部甩向前方，构成动力冲程。化学循环与机械步进严格门控：前一头未结合ATP时后一头难以脱离，形成时序上的棘轮约束。每个ATP释放的自由能因此被定向使用，向后滑移的概率被压得很低，净单向行走得以维持。
The two heads of kinesin bind the microtubule alternately, and ATP hydrolysis docks the neck linker so that a conformational power stroke swings the rear head forward. The chemical cycle is tightly gated with stepping: the trailing head cannot detach until the leading head has bound ATP, imposing a timing-ratchet constraint. Free energy from each ATP molecule is thereby spent directionally, backward excursions stay rare, and net unidirectional motion persists.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
J. Howard 所著《Mechanics of Motor Proteins and the Cytoskeleton》，Sinauer Associates
J. Howard, Mechanics of Motor Proteins and the Cytoskeleton, Sinauer Associates
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780878933341 (2001)
#分子马达 #化学-机械耦合
用光镊拉伸单根双链DNA时，力—伸长曲线在大约65皮牛处出现近恒力平台，这一过伸转变背后发生了什么结构事件？
When optical tweezers stretch a single double-stranded DNA molecule, the force-extension curve shows a near-constant-force plateau around 65 pN—what structural event lies behind this overstretching transition?
在约65皮牛处dsDNA的轮廓长度陡增约七成而拉力基本不变，早期对平台的归属存在两派：一派认为碱基对保持完整、双螺旋整体倾倒成S-DNA，另一派主张氢键断裂生成并行单链。后来的扭转受限拉伸与缺口依赖的荧光标记实验证明，至少在含切口的分子中链分离贡献显著，转变焓及其盐浓度依赖也支持部分熔化的图像。该转变如今成为测量序列特异性解链能与蛋白质作用力的标准工具。
Near 65 pN the contour length of dsDNA jumps by roughly seventy percent while the tension barely changes. Early interpretations split between an intact-base-pair conversion to S-DNA and a rupture of interstrand hydrogen bonds yielding parallel single strands. Later torque-constrained stretching and nick-dependent fluorescence assays established that strand separation contributes substantially at least in nicked molecules, with transition enthalpy and its salt dependence backing a partial-melting picture; the transition now serves as a standard probe of sequence-specific melting energies and protein-induced forces.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
S.B. Smith, Y. Cui 与 C. Bustamante,《Overstretching B-DNA: The Elastic Response of Individual Double-Stranded and Single-Stranded DNA Molecules》,Science 271, 795,1996 (DOI: 10.1126/science.271.5250.795)
S.B. Smith, Y. Cui & C. Bustamante, 'Overstretching B-DNA: The Elastic Response of Individual Double-Stranded and Single-Stranded DNA Molecules', Science 271, 795, 1996, DOI: 10.1126/science.271.5250.795
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1126/science.271.5250.795
#单分子操控 #DNA力学
蛋白质怎么“折叠”出功能？
How does a protein fold into its function?
氨基酸链靠疏水、电荷等相互作用自发卷成特定三维形状，形状决定它能结合什么分子。折叠错了就会失活甚至致病（如阿尔茨海默）。
A chain of amino acids folds into a specific 3D shape driven by hydrophobic and charge forces; that shape decides what it binds. Misfolding can disable it or cause disease.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Anfinsen，《决定蛋白质链折叠的原理》，Science 181 (1973)
Anfinsen, 'Principles that Govern the Folding of Protein Chains', Science 181 (1973)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1126/science.181.4096.223：Principles that
#蛋白质折叠 #构象 #疾病
神经元怎么用电信号“算数”？
How do neurons do arithmetic with electrical signals?
离子通道开合改变膜电位，达到阈值就触发沿轴突传导的动作电位（峰电位）；频率与时机编码信息，网络靠突触强度“学习”。
Ion channels shift the membrane voltage; crossing a threshold fires an action potential traveling down the axon. Frequency and timing encode information, and synapse strength stores learning.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Hodgkin 与 Huxley，《膜电流的定量描述》，Journal of Physiology 117 (1952)
Hodgkin & Huxley, 'A Quantitative Description of Membrane Current and Its Application to Conduction and Excitation in Nerve', Journal of Physiology 117 (1952)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1113/jphysiol.1952.sp004764：A quantitativ
#神经元 #动作电位 #编码
为什么低渗溶液会让细胞膨胀？
Why do cells swell in a hypotonic solution?
低渗溶液溶质浓度低于细胞内，水为平衡化学势经半透膜向内渗透，细胞吸水膨胀甚至破裂；这是渗透压直接作用的例子。
A hypotonic solution has lower solute concentration than inside the cell, so water flows inward through the semipermeable membrane to equalize chemical potential, swelling and sometimes bursting the cell — a direct effect of osmotic pressure.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Serway & Jewett,《Physics for Scientists and Engineers》第9版,Cengage Learning,2013
R. A. Serway and J. W. Jewett, Physics for Scientists and Engineers, 9th ed., Cengage Learning, 2013
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-1-337-55327-8
#渗透压 #半透膜 #低渗
为什么细胞膜静息电位大约负 70 毫伏？
Why is the resting membrane potential about -70 millivolts?
细胞靠钠钾泵把离子“逆浓度”搬运，形成内外离子不均；加上膜对钾更通透，最终静息时内负外正约 -70 mV。
The sodium-potassium pump builds an ion imbalance against concentration, and the membrane's greater leak to potassium leaves the inside about -70 mV relative to outside.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-02
来源 · Source
Hodgkin 与 Huxley，《膜电流的定量描述》，Journal of Physiology 117 (1952)
Hodgkin & Huxley, 'A Quantitative Description of Membrane Current and Its Application to Conduction and Excitation in Nerve', Journal of Physiology 117 (1952)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1113/jphysiol.1952.sp004764：A quantitativ
#静息电位 #钠钾泵 #离子
神经元如何用电信号传递信息？
How do neurons transmit information with electrical signals?
静息时细胞膜内外存在电位差，刺激打开钠离子通道使膜去极化，达到阈值后引发沿轴突传播的动作电位，从而快速传递信息。
At rest a voltage exists across the membrane; a stimulus opens sodium channels, depolarizing it, and once threshold is reached an action potential propagates along the axon, transmitting information rapidly.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-03 · 2 条独立证据
来源 · Source
《费曼物理学讲义》第二卷（电生理章节）
The Feynman Lectures on Physics, Volume II (electrophysiology)
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-7382-0298-3 (2006 Pearson 版，原始版为1963-65 Addis
#动作电位 #离子通道 #神经
肌肉收缩的「滑动丝」模型是什么？
What is the sliding-filament model of muscle contraction?
肌动蛋白细丝与肌球蛋白粗丝相互滑动缩短肌节：肌球蛋白头部结合ATP后摆动牵拉细丝，使肌肉收缩，这是一个由分子马达驱动的过程。
Actin thin filaments slide past myosin thick filaments to shorten the sarcomere: myosin heads bind ATP and swing to pull the thin filaments — a process driven by molecular motors.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录仅给书名，无版次与年份；同一书名常对应多个版次，不臆测具体版本。
《现代物理学评论》— 生物物理力学
Reviews of Modern Physics — biomechanics
#肌肉收缩 #滑动丝 #肌球蛋白
驱动蛋白沿微管行走时每步约8纳米，这个步长与微管蛋白二聚体的排列周期有什么对应关系？ATP水解又是怎样推动其构象循环的？
Kinesin advances roughly 8 nm per step along a microtubule—how does this stride map onto the tubulin dimer lattice, and how does ATP hydrolysis drive its conformational cycle?
微管由α/β微管蛋白异二聚体首尾相接组装而成，纵向重复周期恰好是8纳米，驱动蛋白的两个头部正好落在相邻结合位点上交替前进。ATP与落后头部结合触发颈链对接，将它甩到前方位点；到达后该头部水解释放磷酸，而后头部在下一次ATP结合时才释放ADP。这种握手式门控保证了步进的定向性和高持续性。
Microtubules assemble from head-to-tail α/β-tubulin heterodimers whose longitudinal repeat is exactly 8 nm, so the two heads of kinesin land on successive binding sites and alternate. ATP binding to the trailing head docks its neck linker and swings it to the forward site; after arrival it hydrolyzes and releases phosphate, while the rear head releases ADP only when the next ATP binds. This hand-over-hand gating keeps stepping directional and highly processive.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
Jonathon Howard，《Mechanics of Motor Proteins and the Cytoskeleton》，Sinauer Associates（2001）
Jonathon Howard, Mechanics of Motor Proteins and the Cytoskeleton, Sinauer Associates (2001)
独立核验依据 · Independent verification: 核验依据 1 ISBN 9780878933341 (2001)
#分子马达 #细胞骨架
双光子显微镜为什么能在活体组织中比共聚焦显微镜看得更深,同时光损伤更小?
Why can two-photon microscopy image deeper into living tissue than confocal microscopy while causing less photodamage?
因为激发只发生在焦点。双光子吸收需两个近红外光子几乎同时打到同一分子,概率正比于光强平方,仅焦点亮度足够,焦点外组织不被激发,天然具备光学层切能力,也无需共聚焦针孔。近红外光散射更弱,穿透可达数百微米;单个光子能量更低,光漂白与光毒性随之明显下降。Denk等人1990年据此奠定了该技术。
Because excitation occurs only at the focus. Two-photon absorption needs two near-infrared photons to hit one molecule almost simultaneously, with probability scaling as intensity squared; only the focus is bright enough, tissue elsewhere stays unexcited, giving intrinsic optical sectioning without a pinhole. Near-infrared light scatters less and penetrates several hundred micrometers, while lower photon energy markedly reduces photobleaching and phototoxicity. Denk and colleagues laid the foundation of this technique in 1990.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
W. Denk, J. H. Strickler, W. W. Webb,《Two-Photon Laser Scanning Fluorescence Microscopy》,Science,1990 (DOI: 10.1126/science.2321027)
W. Denk, J. H. Strickler and W. W. Webb, 'Two-Photon Laser Scanning Fluorescence Microscopy', Science, 1990, DOI: 10.1126/science.2321027
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1126/science.2321027
#双光子激发 #活体成像 #光毒性
为什么细胞膜像一个“智能门”？
Why is the cell membrane like a smart gate?
膜上有蛋白质通道，只放行特定的离子或小分子进出，维持细胞内外不同的化学环境。
Protein channels in the membrane let only chosen ions or molecules pass, keeping the cell's inside chemically distinct.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Hille，《可兴奋膜的离子通道》（第3版）
Hille, 'Ion Channels of Excitable Membranes' (3rd ed.)
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL4100399W：Ion Channels of Excitab
#细胞膜 #离子通道 #生物物理
为什么 DNA 会像拉链一样自己“分开”？
Why does DNA unzip like a zipper?
DNA 两条链靠很弱的电吸引力连着，加热或酶的帮助就能像拉开拉链一样把它们分开，方便复制遗传密码。
The two DNA strands are held by weak attractions; heat or enzymes unzip them so the cell can copy its code.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 来源待核验 · Source pending review
来源 · Source
出处备注：著录含书名，但缺版次 / 出版社 / 年份中的一部分，需编辑补全后才能做独立比对。
Watson 与 Crick，《核酸的分子结构》，Nature 171 (1953)
Watson & Crick, 'Molecular Structure of Nucleic Acids', Nature 171 (1953)
#DNA #生物物理 #复制
光学相干层析(OCT)为何特意采用低相干光源,反而能看清组织内部的分层结构?
Why does optical coherence tomography deliberately use a low-coherence source, and how does that reveal layered structures inside tissue?
因为深度被编码在相干长度之中。低相干光仅在样品臂与参考臂光程差小于相干长度(数到数十微米)时才干涉,平移参考镜便逐深度读出背散射信号,相干性本身成了深度选通的门。配合对回波的外差探测,灵敏度足以捕捉微弱的散射光,于是在视网膜这类透明度差的生物组织里也能重建毫米量深的横断面图像,无须切片。
Because depth is encoded in the coherence length. Low-coherence light interferes only when the path difference between sample and reference arms stays below the coherence length of a few to tens of micrometers, so translating the reference mirror reads out backscattered signals depth by depth, with coherence acting as a depth gate. Together with heterodyne detection of the returning wave, the sensitivity captures faint scattering, reconstructing millimeter-scale cross-sectional images even in poorly transparent biological tissue such as the retina without any sectioning.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-04
来源 · Source
Huang, Swanson, Lin & Schuman,《Optical Coherence Tomography》,Science,1991 (DOI: 10.1126/science.1957169)
Huang, Swanson, Lin & Schuman, 'Optical Coherence Tomography', Science, 1991, DOI: 10.1126/science.1957169
独立核验依据 · Independent verification: 核验依据 1 Crossref DOI 10.1126/science.1957169
#低相干干涉 #层析成像 #深度选通